Hi,
pcibios_resource_to_bus() does what I need.
Thanks.
Le 30/12/2012 20:46, Bjorn Helgaas a écrit :
On Fri, Dec 28, 2012 at 2:36 AM, Cédric Cano <ccano@xxxxxxxxxxxxxxxxxxxx> wrote:
Hi,
I'm writing a driver for a DMA engine on the PCI bus. My architecture is a
36-bit PowerPC (MPC85xx).
In my DMA driver, I want to configure the DMA to transfer data to/from a PCI
device.
I get the PCI address of the device BAR with the command pci_resource_start.
pci_resource_start() doesn't give you a PCI bus address; it gives you
a CPU physical address. You ioremap() that address if you want a CPU
to access the BAR MMIO space.
This address is 36-bit but the PCI BAR of the device is 32-bit: I can't use
the 36-bit address to run the DMA.
In kernel documentations, it's advised not to directly read the BAR.
Is there a function which provides the real PCI address i.e. the one stored
in the BAR?
You can use pcibios_resource_to_bus() to convert the CPU physical
address from the pci_dev.resource[] back to a PCI bus address.
sym_iomap_device() does something similar to what you're asking about.
Bjorn
--
To unsubscribe from this list: send the line "unsubscribe linux-pci" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
